What is markdown-preview?

Markdown Preview is a native Mac app for reading and lightly editing Markdown files without opening a code editor or a browser tab. You can drop a .md file onto its icon, set it as the default app for Markdown files, or use the Finder spacebar Quick Look preview, and get a clean, scrollable rendering of the document with a sidebar outline built from its headings that you can click to jump around. Beyond just viewing, it has an Edit Mode with a formatting toolbar for headings, emphasis, lists, quotes, code, and links, so you can make quick changes and save directly from the app. It renders Mermaid diagrams and LaTeX style math equations right inside the preview, both in the full app and in Quick Look, using bundled renderers so this works without an internet connection. There is also in document search, a file metadata inspector panel, adjustable zoom levels for the preview text, and a customizable toolbar following normal Mac conventions. A few features are aimed specifically at people who work with AI tools: an Open in LLM button that sends the current file to Codex, Claude, or ChatGPT with as much file or folder context as those apps support, and a Share and Copy behavior that copies the raw Markdown source text rather than a file link, which is convenient for pasting into a chat window. The app can also register command line tools like mdp so you can open Markdown files or whole folders straight from the terminal, and it can hand a file off to a real code editor such as VS Code, Cursor, or Zed with one click. The app requires macOS 15 or later on either Apple Silicon or Intel Macs, and can be installed through Homebrew or as a signed and notarized download from the releases page. It is open source, built with Swift, and released under the MIT license, with optional anonymous crash reporting that can be turned off from within the app.